Glioblastoma multiforme (GBM) is the most malignant form of all primary adult brain tumors (See Reference 1) Although significant technical advances in surgical and radiation treatment for brain tumors have emerged, their impact on clinical outcome for patients has been only modest (See References 2-4). Of the features that characterize GBM, arguably none is more clinically significant than the propensity of glioma cells to infiltrate into normal brain tissue. These invasive cells render complete resection impossible and confer resistance to chemo- and radiation-therapy. Thus, improved treatment of malignant glioma awaits a way of targeting the dispersing tumor cells in the CNS.